1. Field of the Invention
The present invention relates to a method for creating NC data for the path of movement of a wire electrode, when performing cutting processing by means of wire cut discharge processing.
2. Description of the Related Art
When performing cutting processing by means of wire cut discharge processing, in particular, in cases where the core forming the cutting shape is relatively small, or the like, it is difficult to hold a core which has undergone cutting processing on the work by means of a jig comprising magnets or suction devices, and consequently the core sometimes becomes detached during processing, and parts of the wire or discharge processing device may be damaged by impact of the core when it falls.
Therefore, in order to prevent incidents of this kind in advance, so-called coreless processing, wherein wire discharge processing is conducted along the whole core and the core is completely melted, has been disclosed in Laid-Open Japanese Unexamined Patent Application No. 3-111124, and the like.
This commonly known coreless processing NC data creates a relative path of travel of a wire electrode with respect to a work, the path having a similar shape to the outline of the coreless processing region which expands successively from the centre of the coreless processing region, such that the whole of the cutting shape core region corresponding to cutout shape of the work is removed by wire cut discharge processing.
Conventionally, NC data for coreless processing as described above is created without regard to the size of the cutting start hole for wire cut discharge processing. Therefore, if the processing path moves inside this cutting start hole, the wire electrode will perform a purposeless movement relative to the work, without carrying out processing of any kind. Furthermore, processing time will also be lengthened.